The pipes associated in mythology with the Greek god Pan are the legendary ancestor of the organ. Greek shepherds played a similar instrument, called the panpipes of syrinx, made from strong reeds of different lengths bound together. The organ evolved from such a set of simple pipes with the addition of an air pressure source and a mechanical means of admitting or shutting off the wind as desired.
Hydraulis or Water Organ
The hydraulis, or water organ, was invented in Alexandria (then a center of technological knowledge) around 250 B.C. In this early organ, water pumped into a jar caused the displaced air to sound the variously pitched pipes while keys or levers controlled the wind supply to each pipe. Even though the hydraulis had a very loud, penetrating tone which was not particularly musical, it became one of the most popular instruments of the Roman Empire. Nero was supposedly an enthusiastic player.
In the early A.D. centuries, hydraulic mechanisms gradually were replaced with bellows to provide a source of wind. The earliest representation of a pneumatic organ is found on an obelisk erected in Constantinople around 395 A.D. This instrument was quite small and the weight of two youths standing compressed the bellows. Following the decline and Roman civilizations, organ development passed to the Middle East. Slowly the organ filtered back to Europe, finding a place in the Medieval church as early the 5th century.
The portative organ, carried by a strap around the neck, was first heard of in England in the 12th century and flourished both there and on the Continent in the following three centuries. Played with right hand and blown with the left, the portative was used in church processions, in the homes of merchants, in private chapels of the nobility, and as accompaniment for Miracle and Mystery plays. Both the positive and portative organs soon obtained a more or less complete chromatic keyboard, of a size and touch convenient to be played with the fingers.
Medieval Cathedral Organ
The organ of the Middle Ages was usually an enormous and cumbersome instrument which probably played only a melodic line, due to limited keyboards and no stops to alter volume and timbre. The famous organ constructed at Halberstadt Cathedral in 1361, for example, required wind from twenty bellows pumped by 10 hard-working men. The lowest pipe on this organ was about 29 feet tall and 14 inches in diameter. The size of such pipes, it is assumed, led to the first pedals since the use of the foot would be an easier means of controlling the wind supply.
The positive organ, developing simultaneously with the grand Gothic organs, was so called because it was "placed" in a certain position on the floor or table to be played although it could be moved. Some positive organs had keys so wide that the organist must use his whole hand to play one note. Keyboards first began to appear in the 13th and 14th centuries.